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MASTER5 CNC Real-Time
F A Q
Whats a typical hookup like?
Like this:
What is Real-Time?
In a non-Real-Time CNC controller, it is necessary to very tightly control when a pulses is output to the printer port, then time the pulse, remove the pulse, then time till the next pulse. This means that while a pulse train is being sent out of the Printer port Windows is essentially locked up. You cannot press buttons, surf the web, or interrupt what windows is doing. This means that the maximum frequency of the stepper motor is limited. The smoothness of the motor is also affected because if two pulses are meant to be 100us apart, windows may make it 200us or 50us or 1ms. While it is quite possible to run a stepper motor this way, the end result is not as smooth or as fast as it could be. Master5 uses a system level VXD to control pulsing. This means that the process that looks after pulsing has much more control and can control the pulses to a much higher level of accuracy. Users have reported up to a 300% increase in speed and smoothness. This is due to the ability of a VXD to take control of windows in the background. You can press buttons, interrupt the flow of pulses, or even surf the web, while pulses continue smoothly in the background at system level.
It is possible to defeat the smoothness and accuracy by stressing windows too much. The VXD operates on a timer which looks at conditions 8192 times a second. If windows becomes too busy , this can lower to as bad as 1000 in any particular second. Users report that their systems can get rough if the disk drive is operating too much from other processes as the DMA requirement of the disk drive takes a higher priority than the timer. Generally the faster the CPU, the smoother the system. We think that after using Real-Time control, you won't want to go back.
Does Master5 run on all computers?
No. Unfortunately, some older computers, such as Pentium 133's have had a great deal of problems with intermittent lockups. This has been traced to an inability of the motherboard to handle accessing the main buffer which holds the pulses which have been queued for output. This buffer is approximately 500k and is necessary in order to hold enough pulses to allow the controller program to keep ahead of the pulse controller. Master5 is really two programs running in concert. The main program translates the G-Code, HPGL, or DXF into pulses with the appropriate timing, and sends them to the Pulse controller program. The pulses are then sent out in the proper relationship to the printer port. If the frequency is very high, the buffer empties very quickly (8000 per second) and must be replenished by the translation program fast enough to ensure that the buffer never runs out. Ths means at least 10 seconds of pulses must be stored in the buffer and at times (due to slow moves or ramped moves) up to 20 minutes of pulses might be in the buffer. Some motherboards seem to have a problem accessing this memory fast enough, and this causes a lockup. A fix is actively being sought for this, but in the meantime, I recommend at least a 266Mhz with 48Meg ram.
Do I really need all those control's?
No. Probably not. There is a button at the top of the menu bar which will shut off most of the controls which are rarely used, but there is always someone who wants another control for a special purpose. I have tried to add enough controls for everyone, and the result is a control which looks a lot like a space shuttle control panel. Some people like it, some don't. I hope to find a way to please everyone, but haven't locked on to one yet. Register users are the inspiration for the layout, and I try to give preference to their suggestions.
Whats with the display?
The display is an effort to show the toolpath which will be cut. By pressing the left button and moving in the window, the display can be rotated to any angle. By pressing the right button you can zoom in and out. By pressing the alt key and moving the mouse you can pan to a new center point so you can zoom into a particular point. Some people have experienced a lack of response in the display, this is due to the nature of Master5's real-time pulsing. Maximum priority is given to the pulsing engine. The faster the computer, the better the operation of the tool path display will be. Also large files like photo engravings which can run to 20 Megabytes or more and contain thousands of small moves can also stress the display system, but in the end, the pulse engine get the priority.
My motors only move in one direction?
This is usually caused by swapping the step and dir pins on your outputs. This makes the direction pulse actually move the motor and causes movement only in one direction. Swap the pins in the CNC control icon configuration and try again.
What is Ramp Zero?
Ramp zero is the lowest speed the motors will go except for stop. If a motor is at rest and commanded to move ahead, ramp zero is the first pulse speed. In other words, a motor at rest will receive a pulse, then if ramp zero is set to 100, the next pulse will occur 100hz later, or 10ms and ramp up from there. Most systems run well with about 60-100 in this value, but the mechanics of all systems are different, so feel free to play around. If the ramping starts to get rough, lower the value.
What is Constant Velocity Contouring?
Many arcs and contours are made from hundreds of small segments. If a motor were to ramp up and down for each segment, a contour would be very slow. Generally, CVC is the process of concatenating many line together and ramping up to speed, doing the lines, then ramping down. Sounds easy, but it can be difficult to decide which lines belong in a smooth movement. The mechanics of the system can have an effect here. Master attempts to look at the angular direction of each line segment and decides if the angle of the present move is sufficiently different from the last direction to include or exclude it from the ramped line. The box labeled "Ramp Ctrl" is the angle (in radians) of the value the angle is compared to. a value of .2 (default) is about 11 degrees and works well for most people. Feel free to lower this value for finer ramping (slower cut) and raise it to make the ramping course( faster cut), but beware of gouging if you raise it too much. This will be improved over time, but currently works well enough to lower its priority in terms of upgrades.
What do I get for registering?
Master5 is really support ware. Registering the program get you all upgrades forever. It gives you the right to have your opinions added to the wish list. (see bottom of page). It will give you full functionality in HPGL, GCODE and DXF imports. It gives you line by line translation of the code as it executes. It also makes it possible for me to keep making it better. The time involved in writing Master5 is major, it is currently 47000 lines of code and growing. It is a hobby endeavor and will continue to grow as long as people are supporting it. It is my belief that to make CNC a viable hobby, there must be easy and affordable programs to drive any gadget someone wants to make. Master5 is an effort to be that program. It is not necessary to register to get support for Master5. I try to answer any and all questions within 24 hours, and while that is not always possible I think my record is pretty good.
Why does the translation seem to be wrong?
Because Master5 is a buffering controller, the line by line translation (except in single step mode) will show the current line being translated, but remember the buffer can hold up to 30 minutes worth of pulses in some circumstances, so the translation may be way ahead of the tool. You will see two buffers on the screen, the first is the Pulse buffer, it is how many pulses can be stored to be put out, the Master buffer is how many are waiting to be sent to the pulse buffer.
Why is the motor set by pulses/inch when I use metric?
This was just a programming decision. I will change it someday when I get around to it. Don't hold your breath though, just multiply your pulses/mm by 25.4 to get the proper value.
Material speed doesn't seem to do anything?
Actually it does. But you have to uncheck "Use G-Code speeds" on the main screen to use it. It is the maximum speed the tool path is allowed to go and is set in inches per second.
Will multiple tools be added?
If enough users request it, I will add a tool table. No-one seems to want it right now, but possibly in the future.
What G-Code do you understand?
The latest version of Master5 uses the NIST274 6-axis kernel for its interpreter. My thanks to the authors of the NIST code. It is really great code. It translates G-Code of many flavours and has trouble with no CAM program I have yet seen. It is now fully implemented as 4-axis but only in the release version. Some command do not work but almost any command can be implemented if a registered user requests it. Presently, 90% of commands will work including radius compensation, variables,circular interp, helical milling, etc.
Where do I set up my motors, I saw something flash by that looks like a clock?
Master5's pulse buffer controller, which works in Ring0 code within the operating system is monitored and controlled by a second program called control.exe. When control.exe loads, it shrinks itself to an icon at the bottom of your screen next to the system time. Clicking the CNC icon will open the buffer controller. The ring of lights is the buffer itself, you can see it empty and fill as the program pulses out to the motors. The configure button on the control is where the output pins and input pins are set. Don't use the small configure and fill buttons in the middle of the buffer. They are there to help me help those who need to troubleshoot. Hopefully, you'll never know how they work. :)
Why do I get an emergency stop when I press reset?
Probably, you don't have a table of system hooked to your printer port. Or you have a printer plugged in which is putting a signal on the Emergency stop line. To correct this, select the CNC icon and reconfigure the input pins to negative. This will allow the program to run with out a system attached if you get this error.
What is the Angular checkbox in motor setup?
If this box is checked, the A-Axis will be entered in terms of number of pulses per degree of rotation. If it is unchecked the A-Axis will be entered as number of pulses per inch. Some users have requested the 4th axis be linear, others want angle. I have opted for this method of giving both.
What is I have no A Axis and want to use B axis?
As the code is presently implemented, it is necessary to change your G-Code file from "B"'s to "A"'s and then the file will cut the axis properly provided you have it hooked up to the 4-th axis pinouts. The same is true for a sixth axis "C". It is not possible to run more than 4 axis at once.
My Help files don't work?
Sorry about that, some versions were released with faulty help files. I never use help, so I never noticed. This has been fixed and help should work fine now. The help files aren't great, but I hope to have some eventually. So if you have a question, don't hesitate to ask, it's the price I pay for procrastination.
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